Sistema de monitoramento remoto de para-raios de óxido de zinco baseado na medição da corrente de fuga total.

Abstract

Metal-oxide surge arresters are essential devices in the protection of electrical power system equipment. They contribute to the elevation of reliability, economy and continuity of operation of electrical systems. Because they are connected between the phase and the earth, there will be a leakage current of the order of milliamperes, when subjected to the operating voltage. Leakage current is an indicator of the level of degradation of the surge arresters, most metal-oxide surge arresters monitoring techniques are based on the decomposition of the leakage current, which is composed of a capacitive component and Another resistive. However, this method presents technical and practical limitations, the main one of which is the need to obtain a sample of the voltage applied to the surge arrester to perform the current decomposition. In this work, a system of remote monitoring of metal-oxide surge arresters based on the measurement and analysis of the total leakage current is proposed, exempting itself from the need to measure the voltage applied to the surge arrester. The monitoring system consists of modules for acquisition, transmission, data processing and a web page. The acquisition and transmission are performed by an embedded system located on the earthing conductor of the surge arrester and the remote computer processing module. The transmission system is based on the ZigBee standard. In order to establish remote monitoring, it was necessary to make use of the concept of cloud computing and a development environment web, which combined the necessary tools to create a dynamic site used as interface of the proposed system. The use of a graphical interface allows the real-time monitoring of the degradation state of the surge arrester by means of the waveform of the total leakage current. Laboratory tests are being conducted and good results have been achieved so far.